The only way commits get into master
is by being included in a release branch or a hotfix. And hotfixes are merged into release branches1. So, when you perform the merge of your release branch into master
, it should be a trivial merge and result in the same tree as in your release branch.
To verify this, you can do a git diff release master
(or equivalently, git diff master^2 master
, i.e. diff the merged commit on the master branch with its 2nd parent, which is the tip of your release branch).
[1] This is a special case that's only mentioned in-line in the text, not in the headings, and may not be implemented in the git flow automation scripts.